Serial numbers on Hobie Kayaks are located on the transom or rear of the hull. The number is hand-engraved using a vibration tool. The number is on the underside of the rear of the boat, on the right side. Newer boats have a rectangular, raised, ridge around the serial number to make it easier to find. You can rub a small amount of graphite or soil into the serial number engraving to make it easier to read. Serial numbers use the following format: (example CCMB2345H989)